Kensington Palace revealed the newborn's name on the official Twitter account, also sharing his official title in the tweet.

The Duke and Duchess of Cambridge are delighted to announce that they have named their son Louis Arthur Charles.The baby will be known as His Royal Highness Prince Louis of Cambridge. pic.twitter.com/4DUwsLv5JQ— Kensington Palace (@KensingtonRoyal) April 27, 2018

Prince Louis' Namesake

The highly anticipated announcement of Prince William and Kate Middleton's new baby's name was accompanied with the history behind it.

Their two older children were given names significant to the royal family, with Prince George, 4, sharing a name with many other kings in their lineage, including Queen Elizabeth's father, King George VI.

Princess Charlotte, 2, is given three names honoring their family: Charlotte Elizabeth Diana. Charlotte is the female version of the Prince of Wales Charles, Elizabeth for the Queen, and Diana to pay tribute to William's late mother.

The third child in the family also has Charles in his name, but even his first name is an important one in the family.

Louis is a common family name, with both William and son George having it in their full names.

"It's very much an acknowledgement of a wider heritage," historian Judith Rowbotham explains to BBC, saying that it is also "an affectionate tribute" to Charles and his deep devotion to Lord Mountbatten.

Lord Mountbatten, also known as Prince Louis of Battenburg, was a mentor and very close to the newborn's grandfather Prince Charles, Los Angeles Times reports.

"For me, Lord Mountbatten represented the grandfather I never had," Prince Charles says in a Telegraph report from 2015, talking about the assassination of his mentor in 1979. "So it seemed as if the foundations of all that we held dear in life had been torn apart irreparably."

More Details On The Name

According to Today, Louis is a fairly popular name in United Kingdom where it ranks among the top 100 names. The name has French-German roots and means "famous warrior."

It's not as popular in the United States, although the birth of Prince Louis could change that. While his siblings George and Charlotte did not affect the popularity of their respective names much, Linda Rosenkrantz, cofounder of the Namberry, thinks Louis has a lot of potential to be more fashionable.

"I think Louis has kind of a jazzy feel, as opposed to the other names being considered, Arthur and Albert, so I think it will rise in the U.S.," she says, explaining that the name George "feels a bit stodgy" and Charlotte was already very popular worldwide.